Modeling the dual-fuel combustion of porous lycopodium particles and diesel using an analytical simulation framework

Abstract

In this paper, a comprehensive analytical study is performed to assess the lycopodium-diesel dual-fuel combustion system in counter-flow premixed configuration. The system is modeled as multiple zones that are coupled together via proper boundary and jump conditions on interfaces. According to the respective reaction and transport phenomena in these zones, conservation equations of mass and energy are derived, non-dimensionalized, and solved by Matlab and Mathematica in an analytical way. The porosity of lycopodium particles and the thermal radiation from the reaction zone and the post-flame zones into the preheating zone are considered, in order to improve the realism and accuracy of the modeling. Experimental validation of the derived framework is first carried out with good agreement between our results and the data from the literature. Afterwards, the impacts of parameters such as reactants Lewis numbers, equivalence ratio, and critical strain rate on the flame structure, as well as lycopodium particles' combustion behavior in dual-fuel and single-fuel modes are evaluated and compared. It is found that dual-fuel combustion system enhances the vaporization and ignition of lycopodium particles resulting in a 13% increase in flame temperature. In addition, effects of thermal radiation and porosity of particles on both the flame temperature and position are quantified. The presence of biomass particle porosity and thermal radiation reduces the flame temperature and drive the flame front towards the fuel nozzle.